1. Field of the Invention
This invention relates to absorption cold and warm water systems utilizing solar heat, and more particularly, to an absorption cold and warm water system suitable for providing warm water.
2. Description of the Prior Art
Absorption cold and warm water systems have been in use as heat pumps wherein warm water of low temperature has its temperature raised to a high level, depending on the form of the heat utilized. Various forms of heat have been available, and a system utilizing heat of low temperature, released as exhausts from plants and buildings, is described in NIKKEI MECHANICAL, Feb. 1, 1982.
Meanwhile, in recent years attention has been directed to absorption cold and warm water systems utilizing solar heat in an effort to make effective use of available energy. In one type of absorption cold and warm water system utilizing solar heat, the system functions first as a heat pump to provide warm water in which, when heat source water obtained by solar heating of water reaches an intermediate temperature level, the heat source water is fed to an evaporator of the absorption cold and warm water system and the heat of the heat source water is utilized through heating by a main heat source, such as a burner. A disadvantage of this system, resides in the fact that, when the heat source water has a high temperature, difficulties are experienced in efficiently transferring heat from the high temperature heat source water to warm water through heat exchange, thereby causing a loss of energy to occur.
Meanwhile, when the heat source water has a high temperature, absorption cold and warm water systems operate in different modes. More particularly, in one mode, the system functions as a warm water system in which warm water is produced through heating by the heat source water fed to an ancillary heat source generator of the absorption cold and warm water system or by a main heat source. In another mode, the system functions as a second heat pump by feeding the high temperature heat source water to the evaporator to utilize the heat possessed by the heat source water. Disadvantages of these modes reside in the fact that efficiency of the system is reduced when the temperature of the heat source water drops, and a loss of energy occurs because the system are unable to make effective use of heat source water of a temperature below an intermediate level. In these modes, heat exchange is directly effected between the high temperature heat source water and warm water, making it necessary to use an additional heat exchanger.